Microwave Heating: Alternative Thermal Process Technology for Food Application

This chapter focuses on the principle of a microwave oven, the heat, and mass transfer mechanism, comparison of conventional and microwave heating, factors affecting the microwave heating, advantages of microwaves in food processing operations. The conventional and microwave heating differentiates from each other on the basis of heat transfer direction. The heat flux first reaches the product surface and then transferred to the center of the product due to the thermal gradient in conventional drying. The microwave heating may be used as a substitute for traditional conduction/radiation method and traditional conduction or radiant heating to increase the heat and mass transfer rate and the freeze drying rate, respectively. The frozen food products are tempered or thawed before it processed for further processing in the food industry. Tempering is preferred for the foods those are lower temperatures are acceptable for further processing. Microwave assisted-IR heating is an efficient technique to ensure the desirable properties of food after tempering.